1. Field of the Invention
The present invention relates to a coupling apparatus designed to be quickly connected to a cylindrical member, and more particularly to a coupling apparatus for quickly connecting surface pumping equipment to the casing, tubing or drill stem of an oil or gas well.
2. Description of the Prior Art
When casing is being run in connection with the drilling of an oil or gas well, it sometimes becomes necessary to connect surface pumping equipment to circulate drilling fluid down the well. Typically, this need arises when a tight spot is encountered and drilling fluid is circulated down the well to run the casing past the tight spot and avoid the need for removing the casing and redrilling the hole.
According to the prior art, surface pumping equipment is attached by engaging a swadge having a threaded male lower end with the threaded collar of the casing. Many problems are encountered, however, when engaging the swadge and the casing collar. For instance, the top of the casing typically stands as much as fifteen to forty feet above the floor of the drilling rig creating a hazard to personnel who must work at that height to engage the swadge with the casing collar. In addition, the swadges are quite susceptible to cross-threading when engaged to the casing collar sometimes leading to blowouts under high pressure conditions. Finally, engaging the swadge to the casing collar is a time consuming operation.